Matias Delgado struck twice for the Swiss side as they dominated the opening 45 minutes, and despite Valencia offering more of a threat after the break, Valentin Stocker fired home in injury time to secure a comfortable advantage heading into the second leg in Spain.
Juventus and Benfica both recorded 1-0 wins away at Lyon and AZ respectively to head into the second leg as clear favourites to get through the quarter-final stage.
Read below to see how the night unfolded across Europe.
7.01pmHello, and welcome to Sports Mole's coverage of the fixtures that are taking place in the quarter-finals of the Europa League this evening.
7.04pmSo then, after the first qualifying round of the competition began all the way back in July, we have finally gotten down to eight teams. It's been a long journey hasn't it? Tonight sees the quarter-finals get underway across Europe. Will the games go as expected or will there be a shock in store for one of the favourites?
7.06pmIf you are unaware of who is in action tonight, here's a run down of the last-eight lineup:
7.10pmThe match that catches your eye from that list is Lyon's encounter with Juventus. Lyon have seen their dominance in France come to an end over the past couple of seasons, but with home advantage in their favour tonight, they could gain a result against the Italian giants, who are the clear favourites to win the competition at their home ground in May.
7.14pmThe tie between Basel and Valencia is also expected to be a fiercely fought affair. Basel were unfortunate not to qualify for the latter stages of the Champions League after two victories over Chelsea, and if they can repeat that kind of form against the La Liga side, they could very easily take a first-leg lead to Spain next week. However, since losing heavily to Swansea City on matchday one, Valencia have been superb in this competition.
7.17pmThe winner's of last season's competition, Chelsea, have their hands full in the Champions League, but the runners-up, Benfica, remain in the tournament after edging past Tottenham Hotspur in the last 16. They struggled to put Spurs away in the second leg but that could have purely been down to complacency after a superb 3-1 result at White Hart Lane. They will fancy their chances against AZ, who struggled past a poor Anzhi Makhachkala outfit a couple of weeks ago.
7.21pmThe final match sees Porto face Sevilla. Porto performed tremendously to get past Napoli in the last round, while Sevilla produced one of the performances of the season to fight back from a two-goal deficit from the first leg to win on penalties at Real Betis. That tie really could go either way.
7.24pmPREDICTIONS! Anything could happen in all four matches, but below, are my predictions for the upcoming fixtures.
AZ 1-3 Benfica Basel 2-1 Valencia Lyon 0-2 Juventus Porto 1-1 Sevilla
7.26pmWe've got plenty of time to kill before kickoff. How about I bring you a few stats about the teams that remain in the competition?
7.29pmValencia have the best scoring record of any side remaining in the tournament with 18 goals from their 10 matches. They have also accumulated the most victories with seven to their name. That means that they are currently on a nine-game unbeaten run since their defeat to Swansea in September.
7.32pmSevilla aren't too far behind them with 15 goals, but it's the record of AZ that stands out. The Dutch club have only scored 11 goals from their 10 matches but they are yet to lose in this year's competition. Benfica will be hoping to bring an end to that record later.
7.36pmFrom a disciplinary perspective, AZ have committed 154 fouls, which is 21 more than the next team on the list, Sevilla. Lyon look to be the side who have managed to frustrate their opponents on the most occasions, drawing 153 fouls during their run in the competition.
7.42pmThe top scorer award is still up for grabs over the next six weeks. Salzburg's Jonatan Soriano currently leads the way on eight goals, but with his team already eliminated, that could let in another contender. However, the nearest players in contention who are still active are on four goals - it could be a tough ask for someone to double their tally in such a short space of time.
7.46pmTo coincide with their poor disciplinary record, AZ also possess two of the most common offenders in the tournament. Nemanja Gudelj has committed 22 fouls during his 900 minutes of action, and Aron Johannsson isn't far behind him - the USA international having made 18 fouls in 757 minutes.
7.50pmWe are less than 20 minutes away from kickoff in the respective games. Our main focus will be on developments in France between Lyon and Juventus, but we will have regular updates from the other three encounters in the Netherlands, Portugal and Switzerland respectively.
7.53pmRemarkably, five of the eight teams competing tonight lost their domestic fixtures at the weekend. That isn't much of a confidence booster ahead of such an important match! Benfica and Basel were the only two to earn three points.
7.59pmThe players are beginning to congregate in the tunnel around Europe. We will be underway shortly.
8.05pmWe are underway in France, and the same can be said elsewhere. Bare with me - this could get frantic!
8.07pmIt's a terrific atmosphere in France. The Lyon crowd have come out in full force, but they aren't seeing a whole lot of the ball in the opening stages.
8.09pmRoy Beerens has had an early chance for AZ over in the Netherlands, but his shot was straight at the goalkeeper. Still, it's an encouraging start from the Dutch outfit, who will need to find a way of nullifying Benfica's quality in the final third.
8.11pmCarlos Tevez has spurned an early chance for Juventus. Pablo Osvaldo held the ball up well for the Argentine, but he could only head wide of the post from six yards. That was a great opportunity.
8.14pmValencia have made a fast start over in Switzerland, but as of yet, they haven't found a way to test the goalkeeper. The same can be said of Porto, who are entertaining Sevilla in Portugal.
8.15pmLyon have hardly had a kick so far against Juventus. The Serie A side are having plenty of possession, but it's just that one opening for Tevez that has troubled the Lyon backline.
8.17pmThe chances are few and far between around Europe at the moment. I wish I had some more entertaining news to bring you! All eight teams would have been eager to avoid conceding an early goal and they have achieved their target...so far.
8.20pmBenfica have started slowly in the Netherlands and AZ should have the lead. Viktor Elm was found by a neat pass from midfield, but despite having plenty of space, he could only direct his low shot several yards wide of the post.
8.23pmOver in Switzerland, Valentin Stocker has jinked his way past a couple of Valencia defenders but he could only fire his shot straight at the goalkeeper. Basel are making all of the early running against Valencia, which, despite the stature of the two clubs, shouldn't come as a huge surprise.
8.25pmWe are through 20 minutes in each of the four ties, and we still await the first goal. Surely it's only a matter of time?
8.28pmPorto have already racked up five corners against Sevilla, but their pressure is currently being withstood by the Spaniards. Over in France, Lyon are beginning to have more joy against Juventus, but they have so far been unable to create anything in front of goal.
8.30pmArtur has produced an excellent save to deny AZ's Steven Berghuis. They may have only netted 11 goals in this year's competition, but the Dutch side could have had three in the opening 25 minutes!
8.33pmLyon waste two chances to go into the lead against Juventus! Firstly, Steed Malbranque saw Gianluigi Buffon block his close-range effort before Jimmy Briand poked the ball over the crossbar from six yards. That could potentially be a huge moment in that tie. Lyon need to capitalise whenever they can.
8.35pmJuventus respond through Andrea Pirlo, who plays an immaculate through ball to the advancing Carlos Tevez, but goalkeeper Anthony Lopes comes off his line to smother the shot. It's livening up...
8.37pmValencia have been forced into an early alteration in Switzerland, with Philippe Senderos having to leave the field, presumably because of an injury.
8.41pmIt's raining goals now! Okay, I might have exaggerated a bit, but still, we have goals! Matias Delgado has struck for Basel against Valencia, firing the ball into the corner from the edge of the area.
8.45pmBasel have a second, and it's that man, Matias Delgado, who has struck again! The Argentine midfielder latched onto a cross from Valentine Stocker to prod the ball into the net. Valencia are in all sorts of trouble!
8.47pmRemember, going into this game, Valencia were nine unbeaten in the Europa League. It looks as though that record could be coming to an end. The other two matches this evening remain goalless. We are a few minutes away from half time.
8.49pmAfter being on the back foot for the opening 30 minutes, Benfica have improved against AZ. Guilherme Siqueira and Rodrigo have had efforts on goal without testing the goalkeeper.
8.54pmThe half-time whistle has been blown in all four ties. Unfortunately, only three goals have been netted during the opening period but the action began to liven up near the conclusion of the first 45 minutes.
8.56pmBasel will be delighted with their first-half efforts against Valencia. They were perhaps the marginal underdogs going into the match with the Spaniards, but their pedigree in Europe should come as no surprise. They defeated Chelsea twice and they look to be on their way to beating another major European name.
8.58pmPorto are currently having it their own way in Portugal. Eliaquim Mangala has given them the advantage over Sevilla, but the visitors are sure to be a threat on the break in the second half.
9.02pmIn the other two games, AZ can count themselves unlucky not to be ahead against Benfica, while the contest between Lyon and Juventus has been lacking in goalmouth action. Hopefully that will all change in the second half.
9.06pmWe are back underway. What does the second half have in store for each of the eight teams?
9.09pmIt's been quiet since the restart in France. Both teams are attempting to get a foothold in the match, but the ball is ping-ponging between either side in the middle of the pitch.
9.11pmIt was inevitable that the chances that were wasted in the opening half-hour would come back to haunt AZ, wasn't it? Eduardo Salvio has bagged a vital away goal for Benfica three minutes into the second half.
9.13pmValencia have started the second half on top in Switzerland but they are struggling to keep each of their attack onside. Over in Portugal, Sevilla are maintaining possession without having any threat on the Porto goal.
9.15pmLyon defender Samuel Umtiti's left-footed free kick appeared to be going wide, but it's forced a save out of Gianluigi Buffon. The resulting corner came to nothing, but it's hard not to be impressed by Lyon. They haven't had too many opportunities but they are matching their more illustrious opponents.
9.17pmINJURY! This is a huge blow for Juventus. Carlos Tevez has been substituted after signalling to the bench that he had pulled a muscle. Mirko Vucinic is on in his place.
9.19pmValencia are continuing to press against Basel, with Eduardo Vargas seeing an effort well tipped away for a corner. An away goal for the Spaniards would completely change the complexion of that tie.
9.22pmAfter my positive words about Lyon, they very nearly fall behind against Juventus. Andrea Pirlo is always a threat from set pieces, and his shot from 25 yards was tipped wide by Anthony Lopes.
9.24pmMatias Delgado, who netted Basel's goal during the first half, has been forced off through injury. It isn't going according to plan for the Swiss side during this second half, but for now at least, they remain two goals ahead.
9.26pmI haven't provided many updates from the Porto match during this half, but there is a reason - there hasn't been much to write about! Porto are currently doing what is needed at this stage.
9.28pmJuventus are beginning to pepper the Lyon goal. After a couple of chances were spurned in the matter of seconds, Giorgio Chiellini, who appeared to be in an offside position, drove the ball wide from an acute angle. He should have still found the target.
9.31pmWith just over 20 minutes remaining, the ball has only hit the back of the net four times. Will we get a few more during the closing stages? I hope so!
9.33pmRodrigo has gone close for Benfica. They are pushing for their second, and potentially tie-winning, goal against AZ, but for now, they are having to make do with just the one. However, I'm sure that they would have taken this scoreline if it were offered to them before the match.
9.35pmEduardo Vargas has been in the thick of the action for Valencia during the second half, but he has wasted another opportunity to halve the deficit after heading wide from close range. Basel have hardly had a sniff since the break.
9.38pmJuan Quintero narrowly misses out on doubling Porto's lead but his long-range effort fails to find the top corner. I think Porto will be happy to take a slender advantage to Spain, as long as they can maintain their clean sheet.
9.40pmLyon have thrown on Bafetimbi Gomis, but it's still Juventus who have having the better of the tie in France. Both teams will arguably be content with this result, but there are still 10 minutes for things to change.
9.43pmEduardo Vargas has squandered another opening for Valencia, this time seeing his shot inside the penalty area blocked by a Basel defender. It could be a huge 10 minutes for Valencia.
9.46pmOh dear! What a miss from Mirko Vucinic! The ball from the left reached the Montenegro forward near the six-yard box, but after chesting the ball into his path, he skied his volley.
9.48pmLeonardo Bonucci makes amends for Vucinic's shocking miss by giving Juventus a crucial away goal in Lyon. The ball wasn't cleared by the Lyon defence and it eventually found the defender at the back post, who fired the ball into the roof of the net from six yards.
9.50pmRED CARD! Fernando has received his marching orders for Porto after being handed a second yellow card. The Portuguese side will be relieved that there are just a few minutes remaining on the clock in that one.
9.52pmWe are entering added-on time in all four games around Europe. Can anyone find another goal?
9.55pmHuge, HUGE goal for Basel! After being second best for the second 45 minutes, they have struck in injury-time through Valentin Stocker. That could be enough to take the tie out of the reach of Valencia.
9.59pmThe final whistle has now been blown in all four of tonight's ties. It hasn't been the most eventful of evenings, but some potentially big goals have flown in, in three of the four games. Porto will be happy with their advantage over Sevilla, but it hasn't had the same impact as the goals elsewhere.
10.01pmBenfica and Juventus will be delighted to leave the Netherlands and France respectively with a win and an away goal but the result of the night came in Switzerland, where Basel have opened up a significant lead over Valencia. One away goal in the return leg next Thursday ought to secure themselves a place in the last four.
10.02pmThat will be all from Sports Mole this evening. Thank you for joining us for our coverage of the Europa League tonight, and we hope that you return next Thursday when the names of the four semi-finalists will be decided. Goodbye for now.